The Arteriosclerosis SCOR at Columbia comprises a multidisciplinary and coordinated set of clinical and laboratory research activities within the broad field of arteriosclerosis research. The SCOR program includes projects directed at major questions in the areas of lipid metabolism, hyperlipidemia, atherosclerosis, thrombosis, and coronary heart disease. A central focus of this program is the detailed and extensive study of patients with hyperlipidemia. The major ongoing projects include studies of: (1) cholesterol turnover and metabolism in man; (2) vitamin A transport in plasma; (3) platelet-derived growth factor and the regulation of the growth of human arterial smooth muscle cells; (4) regional myocardial perfusion in patients with coronary atherosclerosis; and (5) intravascular coagulation and thrombosis in patients with hyperlipidemia. A supplemental program is now proposed with the aim of adding new research on plasma lipoproteins and apolipoproteins to the ongoing SCOR program. A project on the metabolism of the plasma lipoproteins in man will be developed by Dr. Blum. This project aims to obtain detailed information about the metabolism of the various plasma apolipoproteins in normal and in hyperlipidemic humans and to delineate normal and abnormal metabolic interrelationships between the different apoproteins and lipoproteins. A project on the intestine and high density lipoprotein (HDL) secretion will be developed by Dr. Glickman. This project aims to define the role of the intestine in the production and metabolism of HDL and in the regulation of plasma HDL levels. In addition, supplemental funds for the core program, particularly for expansion of core biostatistics and data processing, are proposed.